Color Management Primer: Overview

As a photographer, you spend plenty of time capturing the perfect moment, evaluating the quality of the light and understanding how to process, store and print photos in digital darkroom programs like Adobe Photoshop, Lightroom or Apple’s Aperture. The last thing you want to worry about is whether the colors in your photos will be as vibrant, as rich, or as accurate as you saw with your eye and adjusted on your monitor.

That’s why digital photography has become the choice among professionals and amateurs alike; digital ensures your photo preview on the back of your camera looks close to the same as the photo printed on your inkjet, through a digital photo lab or posted online. You get this kind of quality because of effective color management that’s built into every step in the digital workflow and embedded into your photographs. While this process isn’t yet perfect, it is quite robust and requires only a minimal introduction into the technical underpinnings for you to make color management work for your photos.

The goal of this four-part series is to help you improve the color consistency and color accuracy in your digital photography workflow from image capture to print. We’ll begin this month with Part I, a high-level overview of color management—what purpose it serves and how it works. Part II addresses the cornerstone of an effective digital photography workflow—the monitor—with recommendations on how to select an appropriate monitor and how to calibrate and profile the monitor to ensure accurate on-screen color. Part III helps you configure the color management options in the major image editing and correction applications. Part IV tackles color management in the print process, a source of frustration for many photographers.

The knowledge you’ll gain from these articles will take you beyond simple button pushing and give you a deeper mastery of color management because you’ll not only learn how to use it, but you’ll learn how and why it works so well.

The Role of Color Management in Accurate Final Photos

The philosophy of color management is simple. Digital photographs should look the same at every stage of the digital photography workflow. From image capture to print, your photo should look substantially the same, without significant color shifts, changes in contrast or loss of highlight or shadow detail.

In concept, color management is rather straightforward. In practice, it’s significantly more complex. Fortunately, the hardware and software used to implement and support color management has become significantly easier to use and more effective than it was even a few years ago. This makes the benefits of color management accessible to everyone, not just serious professionals with full-time studio assistants. If nothing else, learning to calibrate your monitor effectively, adjust color settings in your imaging software and deftly navigate the options in your printer dialog will make your digital photography workflow faster, more effective and far less frustrating.

ICC-based Color Management: The Foundation of A Successful Workflow

Conventions and standards help make life easier. When you get into any car, you know the gas pedal is on the right and the brake is to the left of the gas. This convention allows a routine to become automatic and prevents you from having to figure out how to work a car every time you get behind the wheel.

This is the idea behind the International Color Consortium (ICC). It is the governing body for color management standards, development and implementation. Like having the gas pedal on the right, standards-based color management makes it easier for software developers to support color management and for end users to use color management effectively by setting standards that most everyone can agree upon using.

The greatest contribution of the ICC is the creation of a modular, ICC-based workflow which makes it easy to prepare a single photo for many different output purposes. Prior to ICC profile, film was scanned and a digital file was created for optimal reproduction on one type of printing press. If a client wanted to change papers or use a different printing method, the file would need to be rescanned as each digital file would only print correctly on one device. This was referred to as “closed loop” color management. The creator of the digital file needed to know exactly how the digital file would be used, otherwise the photo would not print correctly.

We’ve come a long way since then. Today, a photo you create can be printed on your inkjet printer, uploaded to a photo-sharing site where your friends may order prints or a photo book. All this, created from a single file. This is color management in action.

The Secret to Success: Color Profiles

The secret to the success of color management is the adoption and use of color profiles. A color profile mathematically describes the color and tone characteristics of a specific device including paper and ink type, where appropriate. The range of colors reproducible on a given device is commonly referred to as a color space. Through the use of color profiles, we can convert a photo between different color spaces, without significantly changing the appearance of the photo.

You’ve already been using ICC-based color management whether you realize it or not. Whenever you print a photo on your inkjet printer, a conversion occurs between the color space selected on your digital camera or scanner and the printer’s color space used to ensure the colors are correctly matched between your camera and the printer. Often, this takes place automatically behind the scenes in the print software. If your print looked good, this process was successful. If not, poor color management was to blame.

To help ensure the next print is successful, let’s look at how color management works from a deeper perspective.

Readers' Comments

Great article on an important topic - I can't wait for the upcoming installments.

I have to admit, though, that the "editing" color space is very confusing.

Device profiles seem to serve the purpose of resolving the various device quirks so that "red" on my monitor is the same as "red" on my printed image. So if my image has "red" in it, my monitor looks at its profile to see, given its characteristics, how to display "red". And my printer looks at its profile to see, given its ink and paper characteristics, how to display "red".

Makes sense.

But editing profiles?

First of all, whether the camera saves a profile in a JPG or whether a profile is applied during RAW conversion, I don't see a device profile for the camera. Surely the sensor in my Nikon D80 would produce a different shade of "red" than its Canon competitor. So where is the step where the camera looks at its profile to see, given its characteristics, how to save a "red" image? The first step we see is that either the camera saves an EDITING profile in the JPG or my RAW converter applies an EDITING profile. Where's the camera device profile?

Also, editing profiles seem to almost go AGAINST the concept of color management, by looking at the data the camera produced and coming up with different interpretations of that value. So what my camera says is "red", sRGB might say is "dark red" but Adobe RGB says is "not-so-dark red". So using two different editing profiles gives me two different results... I don't get how that is helping me! :)

And lastly, while device profiles seem to be instructions for how to accurately produce a reference color, editing profiles seem to be the opposite, which is given a reference color what are the instructions for interpreting that color?

Great article. Also, I cannot wait for installments 2-4. This is the level of instruction I need. Right on track with your message to my need. While I did not learn alot from Article 1, I did learn. Nice foundation for the future. My complaint is always writers start "too high". You started at the right level. Thanks, Karl

Thanks Jay for a great article pitched for people with some knowledge of the subject, but not in some of its finer details.

Something you don't touch on, but would be helpful to me, is how the different platforms affect colour management. I'm running one of the last eMacs (I REALLY like its CRT) and standardly have the monitor set to 2.0 when colour correcting images — taking an exact median between the 1.8 Mac normal setting and PC 2.2 setting — so that when they are uploaded to an image library something reasonable is seen by viewers on both platforms. But obviously this isn't ideal, as they are always going to appear 'too dark' to some people and 'too light' to others.

This is just excellent; thank you. I'm fine in a darkroom but frequently frustrated by digital printing, so it's spot on for me! In later parts, is it possible to cover Capture NX as well as Photoshop, please?

Ed, thanks for your comments. Let me try and clarify the confusion around editing spaces. Most ICC profiles are created by taking measurements of the color response from a particular device (e.g. Monitor and Printer Profiles). This ensures your photo reproduces correctly on that device. The downside is that the compensation needed to, say, make a black and white photo appear neutral on your monitor can be pretty severe. This would make it maddening to try and perform corrections using a monitor profile. Corrections would be inconsistent and effective only for that particular device. If you switch computers, you'd have to re-correct the photo all over again. Editing spaces are mathematically created for an intended purpose and are therefore gray balanced, easy to port between computers & applications and far more effective to use. There is a need for different editing spaces for different purposes. SRGB is ideal for the web, Adobe RGB is ideal for print, and so forth. I'll get into that more in part 3. If I don't answer your questions fully in that article. Please re-post, or contact me directly and I'll be glad to help.

Great Article, may I have permision to share with the members of my camera club. We are doing mini education series on digital photography and are just getting to downloading image, file management and color management.

I am looking forward to the rest of these articles as the subject is timely for me and I like the approach taken thus far. Any chance on getting the monitor portion sooner? It's something I need to deal with now and I am interested in suggestions for viable monitors of the less expensive variety. Also, when it comes to color space, the first installment only mentions Pro Photo RGB in passing. I am wondering if Pro Photo will become the new default standard for photo editing since from what I understand it is the space Lightroom 2 operates in. Great information so far, please keep it coming.

Thanks for a timely and excellent start to the subject of digital colour management. I too look forward to the rest of the series, as I have just gone through the stage of achieving monitor calibration, but am still being frustrated with the fine tuning of printer output for the variety of papers I like using. Nearly like going back to my darkroom days in printing a series of test strips before daring to load the high quality A3 paper into the printer!

Hi, I also enjoyed your informative article. I have a 17" Mac Book Pro which I would like to calibrate using my GreyTag Macbeth Eye One. Would you recommend I use the Auto calibration or the Professional calibration?

Cheryl, I recommend using the Advanced calibration option in the EyeOne Match software. Be sure to select the Laptop option when prompted. The monitor calibration article is nearing completion and will contain specific recommendations for setting the white point, gamma and luminance in your monitor calibration software.

Hi Jay, thanks for the tips... I know this is going to sound a bit dim but can one calibrate a scanner using an 18% grey card?
For example I scan the card, then give it a profile of R185 G185 B185 and from then on use that profile as a "yardstick" in the same manner as used in a darkroom procedure?
Sorry to ask such a banal question but I am new to digital photography, after spending the last 25 years using "wet processes" I am finding the transition a little bewildering.
Thank you again for the essay, it really helped.

The subject is well presented but I have a doubt. I use Nikon digital reflex (D3 or D200) with Adobe RGB (1998) as color space even if I usually take pictures in raw format (but sometimes I use Jpeg).
I convert raw pictures with Adobe Lightroom (without changing color space) and Lightroom presents in its last version the panel "Camera calibration". I have searched for some papers where this calibration is explained and it seems me that in practice (by photographing the Kodak color checker) I have to adjust the various colors in order to reproduce the exact colors of color checker.
Now, if it is true that the color space of camera and Lightroom are the same, why must I reconstruct a calibration curve? Perhaps the color space of the camera can be slightly different from calculated Adobe RGB (1998) (because of the features of the lenses or of the software or of exposure meter)? or even if the color space is the same the profile leading from a color to another in the space is slightly different?
Perhaps I have a misunderstanding on the basis, concerning the difference between color space and profile but however if you can give an explanation I will be grateful.
Roberto

Calibrating any device requires more than one point of reference. While an 18% gray card would be a start to dial in the midtones, a series of gray patches would be better (highlights, midtones and shadows. Better still is to use a scanner profiling package to automatically measure a large number of colors and calculate a look up table for all the colors possible in your scans.

You'll have the best results calibrating a scanner for scanning transparency film and black and white film, but difficulty calibrating color negative due to the orange mask and the variance in the orange mask due to exposure and development.
Jay

Roberto,
The calibration feature in Lightroom and Adobe Camera Raw (Photoshop) works differently than the ICC-based system explained here. Raw files are a special class of photos and as such don't work with ICC based color management. The calibration panel is designed to allow you to photograph a 24-patch Gretag Macbeth color checker, then tailor the Red, Green and Blue, hue and saturation so the colors of the color checker, and presumably all other colors, appear correct in ACR.
Recently, Adobe released the DNG Profile Editor, which makes this process far more efficient. You can view a tutorial on the use of the DNG Profile Editor on my Web site: http://www.prorgb.com/dng-profile-editor1.

Additionally, Adobe released new camera profiles for use in ACR, which are designed to match the in-camera JPEGs. So, if you shoot raw+JPEG, you won't see significant differences between the colors in the Raw and the JPEG versions.

On a final note, the Calibration tab is ignored when JPEGs are brought into Lightroom or ACR. Instead, the embedded color profile (Adobe RGB, or sRGB) is used for displaying colors.

Any tutorial on color management should cover how the implementation of it is broken on both Windows and Macintosh systems, and how to best work around this when putting photos on the Web.

Executive summary:

Windows is broken because it doesn't color manage at all. It just blindly assumes things are in the sRGB color space. So images in any other color space won't display properly in a Windows browser.

Macintosh is broken because it fails to properly display images with no embedded color profile. 99% of such images on the Web are in the sRGB color space (because that's what Windows expects), yet the Mac simply ships those bits over to the monitor with no conversion... effectively assuming that such images are in the Mac's native color space (but they're not; Macs don't use sRGB as their native color space). Upshot is that images which look good on Windows look washed out and desaturated on the Mac.

The best workaround is to embed color space information in each file displayed on the web (so it can display OK on the Mac), and always use the sRGB color space (so it will display OK on Windows) for such files. Even then, many Mac browsers (Explorer and Firefox are notorious for this) will ignore any color space information and just ship raw bits to the monitor. When I last experimented, Safari was the only Mac browser I found which honored color space information.

An excellent article! Minor point, you might want to change the bit about "(there is no Color Match RGB device to measure)" because there is (or was), namely the Radius Pressview. Unlike other RGB working spaces, its not totally synthetic. If you substitute sRGB or Adobe RGB (1998) or ProPhoto RGB, you'd be spot on.

The PressView predates Photoshop 5, working spaces etc. At the time, ColorMatch RGB WAS the exact color space of the PressView after calibration. We didn't have RGB working spaces yet which were totally independent of the display. The PressView was truly a reference display that could, after calibration hit a very specific color space which the designer (Karl Lang) named ColorMatch RGB.

ColorMatch RGB was useful for early users of Photoshop who needed consistent previews based on an exacting target (ColorMatch RGB). The TRC of the space was designed at 1.8 specifically for those working in print and prepress. ColorMatch uses 1.8 because there is less quatization on the way CMYK. The eye is closer to 2.2 (luminance response) but presses have dot gain. Using a source space that is a little lighter reduces the quantization when you correct for press gain. (few people know that Xerox PARC and Apple used 1.8 as a source space because of the natural dot gain of toner based laser printers.)

Also when a PC user looks at a not color managed ColorMatch Image in their well lit office on their sRGB display there is less of a chance that they will screw with it, a second bonus.

Excellent text!
It is clear you've gone to the trouble of experimenting with all the possible variables under user control. Thanks for a very informative piece on colour image procesing.
I think it would be a bit of an improvement if you added a few dates on certain facts, as these technological improvements and agreements tend to change with time and with new techniques, discoveries, and new materials.
Congratulations!

Thanks for your comment. Do you have specific items you'd like referenced with dates? The fundamentals of ICC-based color management haven't changed much in at least 10 years. Certainly, in the subsequent color management articles, there are opinions that evolve over time. Monitor white point and luminance, being two that are receiving a lot of discussion right now. These would warrant some additional background information. In reviewing this particular article, I don't see much that is likely to change. Perhaps I'm glossing over something that could use a deeper analysis. Could you provide me with some additional information?

Jay: I have been printing my prints without knowing what profile I was using and they would not turn out the same as my monitor. I had no idea about "Color Management". Is it possible to go back to my prints and change the profiles according to your lesson? Or, once the profile is embedded in the print....is the print doomed?

This information has been great for me. I am eager to find out more about Color Management and the workflow. I really need help.

Delores, Thank you for your comment. I'm glad this article was a helpful introduction for you. If you've saved your original layered Photoshop document, you'll be able to incorporate the color management techniques outlined in these articles the next time you make your prints. I'd suggest reading the article on monitor calibration to make sure you can trust your screen, then the article on printing before you jump into your next round of prints to ensure you have all the information you need to color manage the print process successfully.